Clean and Green Approach for Synthesis of Various Derivatives of [1,3]Oxazine in Sustainable Aqueous Hydrotropic Medium

Abstract

An efficient and sustainable synthesis of 2,3-dihydro-2-phenyl-1H-naphtho[1,2-e] [1,3]Oxazine and 3,4-dihydro-3-phenyl-2H-naphtho[2,1-e][1,3]oxazine derivatives has been achieved by the one-pot, multicomponent condensation of α- or β-naphthol (1 mmol), an aniline (1 mmol) and formaldehyde (2 mmol) using aq. 30% NaPTS hydrotropic solution at room temperature. The aqueous hydrotropic medium is nontoxic, reusable, inexpensive, and easily available. This improved strategy allows the very comfortable preparation of a wide variety of substituted [1,3]Oxazine derivatives under mild reaction conditions with a maximum yield of up to 92%, easy isolation of purified compounds, and an eco-friendly approach under sustainable development. This organic transformation shows a clean and green protocol for the synthesis of 2,3-dihydro-2-phenyl-1H-naphtho[1,2-e] [1,3]oxazine and 3,4-dihydro-3-phenyl-2H-naphtho[2,1-e][1,3]oxazine derivatives.

Graphical Abstract

Keywords:

• Green synthesis
• [1,3]oxazine
• aqueous hydrotrope
• β-naphthol/α-naphthol
• formaldehyde
• aniline

Acknowledgments

One of the authors Aboli Sapkal gratefully acknowledge for the financial support from Sarthi Research Fellowship Government of Maharashtra. We also gratefully acknowledge the financial support from the Department of Science Technology (DST-SERB) for awarding major research project under the scheme Empowerment and Equity Opportunities for Excellence in Science, University Grant Commission (UGC), New Delhi for awarding major research project, Rashtriya Uchchatar Shiksha Abhiyan (RUSA) and the Y. C. Institute of Science, Satara for providing necessary facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).